std::rank
From Cppreference
| C++ Standard Library | ||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Utilities library | ||||||||||||||||||||||||||||
| Type support | ||||||||||||||||||||||||||||
| ||||||||||||||||||||||||||||
| Defined in header <type_traits>
| ||
| template< class T >
struct rank; | (C++11 feature) | |
If T is an array type, provides the member constant value equal to the number of dimensions of the array. For any other type, value is 0.
Contents |
Inherited from std::integral_constant
Member objects
| value | the number of dimensions of T or zero (public member object) |
[edit] Equivalent definition
template<class T> struct rank : std::integral_constant<std::size_t, 0> {}; template<class T> struct rank<T[]> : public std::integral_constant<std::size_t, rank<T>::value + 1> {}; template<class T, size_t N> struct rank<T[N]> : public std::integral_constant<std::size_t, rank<T>::value + 1> {}; |
[edit] Example
#include <iostream> #include <type_traits> template<typename A> void print_dim(const A&) { std::cout << "The array has " << std::rank<A>::value << " dimensions\n"; } int main() { int a[1][2][3]; print_dim(a); print_dim(a[0]); }
Output:
The array has 3 dimensions The array has 2 dimensions
[edit] See also
| checks if a type is an array type (class template) | ||
| obtains the size of an array type along a specified dimension (class template) | ||
| removes one extent from the given array type (class template) | ||
| removes all extents from the given array type (class template) | ||
